1. Field of the Invention
This invention is in the field of liquid dispensing devices of the resilient wall type wherein the resilient wall is part of a fluid pressure generating bulb, is removable from the container to be part of a kit or assembly for the container and whenever the fluid pressure causes the dispensing operation to take place emits liquid held in the container through an outlet tube. The invention is also in the field of compressible resilient closures for flasks wherein the closure is of the stopper type and is provided with separate inlet and outlet passages.
2. Description of the Prior Art
Washbottles of the conventional type have been used in the teaching of laboratory chemistry and analytical chemistry for a long time, an example of the use of a washbottle for the intermittent delivery of fluids being shown in MacLean, U.S. Pat. No. 1,600,189 granted Sept. 14, 1926.
Washbottles utilizing a replaceable bulb as pump to bring pressure into a washbottle, rather than using the mouth of the user are generally regarded as washbottles of the sanitary type and an example of this type of washbottle is disclosed in U.S. patent to Severson U.S. Pat. No. 2,105,957 granted Jan. 18, 1938.
Squeeze bulb dispensers such as used in automatic burettes shown in Geyer, U.S. Pat. No. 1,993,001 granted Mar. 5, 1953, or in pipettes as disclosed in Sharples, U.S. Pat. No. 553,044 granted Jan. 14, 1896, have employed T tubes or open tubes in order to permit the control of liquid dispensing under pneumatic pressure.
However, in all of the prior art patents, the stopper or closure through which the open or T tube is fitted in order to pressurize the liquid contents of the flask has been a one piece stopper either of the complex blown glass shape as in Geyer or of the specialized glass shape shown in Sharples. The expense of these blown glass closures makes these laboratory devices prohibitive in cost for most chemistry classes while breakage and replacement is a serious problem.
The two piece closure in Perelson, U.S. Pat. No. 2,342,215 granted Feb. 22, 1944, is specifically adapted to hold a needle forming a passageway to fill a hypodermic syringe but there is no concept of a low cost compressible rubber stopper as in Severson U.S. Pat. No. 2,105,959 to permit a simple finger manipulation for dispensing liquid utilizing the stopper or closure for all of the passageway structure on the outside as well as the inside of the flask to thereby control dispensing and avoid the expense of the glass stopper in Geyer or the complex glassware in Sharples and Geyer.
It is surprising to find that a simple two piece closure with inverted U passageway in accordance with the invention can improve the efficiency of assembly and manufacture of a sanitary washbottle while reducing the cost over that of the single stopper heretofore used as in Severson U.S. Pat. No. 2,105,957.